Shoulder implant assembly

ABSTRACT

An implant assembly and associated method for selectively performing reverse and traditional arthroplasty for a shoulder joint that includes a humerus and a glenoid. The implant assembly may include a head, a cup, a humeral stem and an adapter. The method includes inserting the humeral stem to the humerus and connecting a male taper of the adapter to a female taper of the head. For reverse arthroplasty, the method includes attaching the adapter to the glenoid and the cup to the stem. For traditional arthroplasty, the method includes attaching the adapter to the humeral stem and the cup to the glenoid. The method also includes articulating the head with the cup.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. patent applicationSer. No. 10/680,924, filed on Oct. 8, 2003 (now U.S. Pat. No. 7,175,663,issued Feb. 13, 2007). The disclosure of the above application isincorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to an implant assembly for shoulder jointreplacement.

BACKGROUND OF THE INVENTION

A natural shoulder joint may undergo degenerative changes caused by avariety of reasons. When these degenerative changes become so faradvanced and irreversible, it may ultimately become necessary to replacea natural shoulder joint with a prosthetic shoulder joint. In thetraditional implantation of a shoulder joint prosthesis, the naturalhead portion of the humerus is resected and a cavity is created in theintramedullary canal of the host humerus for accepting a humeralcomponent. The humeral component generally includes a stem, and a headportion, which is used to replace the natural head of the humerus. Oncethe humeral component has been implanted, the glenoid cavity positionedat the scapula may also be resected and shaped to accept a glenoidcomponent. The glenoid component generally includes an articulatingsurface or cup which is engaged by the head portion of the humeralcomponent. Modular designs for the humeral and glenoid components arecurrently available for the traditional shoulder arthroplasty, andcomponents of different sizes or shapes are at the disposal of thesurgeon performing the operation.

The traditional shoulder joint implantation requires that the rotatorcuff muscles be present and functioning normally. When this is not thecase, a reverse shoulder prosthesis may be preferable. In the reverseshoulder prosthesis, the humeral component includes a stem, and a cupconnected to the stem. The glenoid component supports a head whicharticulates with the cup.

It is not always practical to determine well in advance of the procedurewhether a reverse or traditional shoulder prosthesis should be used. Itis, therefore, desirable to provide a selection of modular componentsthat can be combined for use in traditional as well as reverse shoulderarthroplasty, with the goals of increasing flexibility and choice andfor providing interchangeable and easy to use components that are alsocost effective.

SUMMARY OF THE INVENTION

One embodiment of the invention provides an implant assembly for ashoulder joint that has a humerus and a glenoid. The implant assemblymay include a humeral stem configured to be inserted in the humerus, anda head bounded by a convex surface and a planar base that has a femaletaper. The implant assembly also includes an adapter having a tray andan male taper. The tray may be configured to be attached to the glenoid.The male taper of the adapter is configured to be received in the femaletaper of the head. The implant assembly also includes a cup that can beattached to the stem. The cup has a concave surface that is configuredto articulate with the convex surface of the head.

Another embodiment of the invention provides an assembly of implantcomponents for a shoulder joint having a humerus and a glenoid. Theassembly includes a humeral stem, a head having a convex surface, and acup configured to articulate with the convex surface of the head. Theassembly includes a glenoid adapter for a reverse shoulder arthroplasty,and a humeral adapter for traditional shoulder arthroplasty. The glenoidadapter is configured to connect the head to the glenoid when the cup isconnected to the humeral stem. The humeral adapter is configured toconnect the head to the humeral stem when the cup is connected to theglenoid. The same adapter may be used as a glenoid and as a humeraladapter.

Another embodiment of the invention provides an assembly of implantcomponents for a shoulder joint having a humerus and a glenoid. Theassembly includes a plurality of humeral stems, a plurality of heads,and a plurality of cups configured to articulate with the heads. Theassembly also includes a plurality of glenoid adapters for a reverseshoulder arthroplasty, and a plurality of humeral adapters fortraditional shoulder arthroplasty. Each glenoid adapter is configured toconnect one of the heads to the glenoid when one of the cups isconnected to one of the humeral stems. Each humeral adapter isconfigured to connect one of the heads to one of the humeral stems whenone of the cups is connected to the glenoid.

Another embodiment provides a method for selectively performing reverseand traditional arthroplasty for a shoulder joint that includes ahumerus and a glenoid. The method includes providing a head, a cup, anda humeral stem. The method also includes providing a humeral adapter fortraditional arthroplasty, and providing a glenoid adapter for reversearthroplasty. Further, the method includes selecting one of the humeraland glenoid adapters, and performing the corresponding arthroplastyutilizing the head, the cup, the humeral stem and the selected adapter.

Another embodiment provides a method for selectively performing reverseand traditional arthroplasty for a shoulder joint that includes ahumerus and a glenoid. The method includes inserting a humeral stem tothe humerus and connecting an adapter to a head with mating male andfemale tapers. The method also includes selectively attaching a base ofthe adapter to the glenoid for reverse arthroplasty, and to the stem fortraditional arthroplasty, and selectively attaching a cup to the stemfor reverse arthroplasty, and to the glenoid for traditionalarthroplasty. Further, the method includes articulating the head withthe cup.

Further areas of applicability of the present invention will becomeapparent from the detailed description provided hereinafter. It shouldbe understood that the detailed description and specific examples, whileindicating current embodiments of the invention, are intended forpurposes of illustration only and are not intended to limit the scope ofthe invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from thedetailed description and the accompanying drawings. The components inthe drawings are not necessarily to scale, emphasis instead being placedupon illustrating the principles of the invention.

FIG. 1 is an exploded view of an embodiment of an implant assemblyaccording to the invention, shown in a traditional shoulderarthroplasty;

FIG. 2 is an exploded view of an embodiment of an implant assemblyaccording to the invention, shown in a reverse shoulder arthroplasty;

FIGS. 3 a-3 d are side views of embodiments of an adapter according tothe present invention;

FIGS. 4 a-4 e are side views of embodiments of a cup according to thepresent invention; and

FIG. 5 a is an exploded view of an embodiment of an implant assemblyaccording to the invention, shown in a traditional shoulder arthroplastyand with alternative heads and humeral adapters;

FIG. 5 b is an exploded view of an embodiment of an implant assemblyaccording to the invention, shown in a reverse shoulder arthroplasty;

FIG. 6 a is an exploded view of an embodiment of an implant assemblyaccording to the invention, shown in a traditional shoulderarthroplasty;

FIG. 6 b is an exploded view of an embodiment of an implant assemblyaccording to the invention, shown in a reverse shoulder arthroplasty;

FIG. 7 is an exploded view of an embodiment of an implant assemblyaccording to the invention, shown in a reverse shoulder arthroplasty;

FIG. 8 is an embodiment of a assembly of components for shoulderarthroplasty according to the invention;

FIGS. 9 a-9 c are side views of embodiments of heads according to theinvention;

FIGS. 10 a-10 c are side views of embodiments of adapters correspondingto the heads of FIGS. 9 a-9 c;

FIGS. 11 a-11 c are side views of embodiments of head bearings;

FIG. 12 is an exploded view of an embodiment of an implant assemblyaccording to the invention, shown in a traditional shoulderarthroplasty;

FIG. 13 is an exploded view of an embodiment of an implant assemblyaccording to the invention, shown in a traditional shoulder arthroplastywithout a humeral stem;

FIG. 14 is an exploded view of an embodiment of an implant assemblyaccording to the invention, shown in a reverse shoulder arthroplastywithout a humeral stem;

FIG. 15 is an exploded view of an embodiment of modular adapter, shownwith glenoid and humeral stems; and

FIG. 16 is an exploded view of an embodiment of modular adapter; shownwith glenoid and humeral stems.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following description of the preferred embodiments of the inventionis merely exemplary in nature and is in no way intended to limit theinvention, its application, or uses.

Referring to FIGS. 1 and 2, there is shown an embodiment of an implantassembly 100 for a total shoulder joint replacement. The implantassembly 100 is configured to be implanted between a resected humerus102 and a glenoid cavity (“glenoid”) 104 of a scapula 106 in one of twoways, i.e., in a traditional arthroplasty depicted in FIG. 1, or in areverse arthroplasty depicted in FIG. 2, by selecting and/orreconfiguring appropriately the components of the implant assembly 100.The implant assembly 100 includes a head 108, a cup 110, and an adapter112. The implant assembly 100 may also include a humeral stem 114 thathas a proximal end 115 and a distal end 117.

Other embodiments of the implant assembly are shown in FIGS. 5 a, 6 a,12, 13 for traditional shoulder replacement, and in FIGS. 5 b, 6 b, 7and 14 for reverse shoulder replacement. FIGS. 3 a-3 d, 4 a-4 e, 9 a-9c, 10 a-10 c, 11 a-11 c show representative embodiments of variouscomponents. FIGS. 15 and 16 show embodiments of a modular adapter 113.FIG. 8 shows an embodiment of a component assembly (kit) for shoulderreplacement 800 showing different sizes of representative components. Itshould be understood that the component assembly 800 in FIG. 8 is onlyillustrative of the inclusion of different sizes of each component andit is not limited by the type of components actually shown. For example,the component assembly 800 may include different sizes of each of theheads 108 shown in FIGS. 9 a-9 c, different types and sizes of adapters112, different sizes and types of cups 110, etc. Like reference numeralsrefer to like components. When clarity requires to differentiate betweendifferent embodiments of the same component, an alphabetic character isattached to the reference numeral. For example, the head 108 isreferenced as head 108 a and head 108 b to distinguish between twodifferent head embodiments, as shown in FIG. 5 a.

In the embodiment shown in FIGS. 1 and 2, the head 108 is bounded by aconvex surface 116, which may be, for example, a hemispherical surface,and a base 118, which may be a substantially planar surface. In oneembodiment, the base 118 may be modularly connected to the head 108. Afemale taper 120 with tapered inner walls 122 extends from the base 118into the head 108. The convex surface 116 of the head 108 is shaped toarticulate with a concave surface 124 of the cup 110 to allow forshoulder joint movement. Such articulation may be centered or eccentric.This and other embodiments of the head 108 are shown in FIGS. 9 a-9 c.In the embodiment of FIG. 9 a, the head 108 has a male taper 140. In theembodiment of FIG. 9 b, the head 108 has a female taper 142.

Referring to FIGS. 1 and 2, the cup 110 may include a back surface 126that may be configured to be selectively attached to the humeral stem114 in reverse shoulder arthroplasty, or to the resected glenoid 104 inthe traditional shoulder arthroplasty. Alternatively, the cup 110 may bechosen from a number for available cups, such as those shown in FIGS. 4a-4 d, some of which are better suited to either reverse shoulderarthroplasty or traditional shoulder arthroplasty. For example, the backsurface 126 of the cup 110 may be a substantially planar surface whichcan be attached with cement or with mechanical fasteners, such asscrews, to the humeral stem 114 or to the appropriately resected glenoid104. Alternatively, as shown in FIG. 4 c, the back surface 126 may beslightly convex. In the embodiment shown in FIG. 4 b, the back surface126 may include a number of pegs 127 for attachment to the glenoid 104.In the embodiment shown in FIG. 4 d, the cup 110 may include a maletaper 121 which is received in a corresponding female taper 123 of theproximal end 115 of the humeral stem 114. FIG. 4 e shows a bearing 192of a modular cup 110 that has a concave surface 124 and a female taper144 adapted to receive a modular glenoid stem 130 or modular humeralstem 136, such as those shown in FIGS. 15 and 16 in connection with themodular adapter 113. The bearing 192 may also be used with theembodiments of FIGS. 13 and 14, as is described below.

Referring to FIGS. 15 and 16, the modular adapter 113 may include a body150 with a male taper 152 and a female taper 154. The female taper 154is adapted to receive a glenoid stem 134 for the reverse shoulderarthroplasty and a humeral stem 136 for the traditional shoulderarthroplasty. The male taper 152 is adapted to be received in the femaletaper 142 of the embodiment of the head 108 shown in FIG. 9 b or in thefemale taper 120 of the embodiment of the head 108 shown in FIG. 9 c,for example.

In general, the adapter 112 may be modular, such as the adapter 113 ofFIGS. 15 and 16, or a monolithic adapter. The adapter 112 may be asingle, one and the same, adapter that can be used selectively in boththe traditional and the reverse shoulder arthroplasty, or it can bechosen from a number of available adapters of an assembly of components,such as those shown in FIGS. 3 a-3 d, depending on which arthroplastyprocedure is to be performed. Some of these adapters 112, such as, forexample, the adapter shown in FIG. 3 c, may be specifically configuredfor use with reverse arthroplasty, because they incorporate the glenoidstem 134, either modularly or monolithically.

In one embodiment, the adapter 112 may include an adapter tray 128 andan extension or male taper 130 that can be press-fitted into the femaletaper 120 of the head 108. For the procedure of traditional shoulderarthroplasty, the tray 128 is attached to the proximal end of thehumeral stem 114, as shown in FIG. 1. For the procedure of reversearthroplasty, the tray 128 is attached to the glenoid 104, as shown inFIG. 2. In the embodiments of FIGS. 3 a and 3 c, the tray 128 mayinclude a curved portion 132 shaped to conform with a portion of theglenoid 104. It may also include the glenoid stem 134, which is insertedinto the glenoid 104. The adapter may be attached to the glenoid 104with fasteners, such as screws.

Referring to the embodiment of FIG. 3 a, the tray 128 may also besubstantially planar. It will be appreciated, however, that othershapes, in addition to those shown in FIGS. 3 a-3 d, are possible forthe tray 128 depending, for example, on the various ways the tray 128 isbe attached to the humerus 102, to the humeral stem 114, or to theglenoid 104. Furthermore, the adapter 112 may be modular, such that themale taper 130, the tray 128 and the glenoid stem 134 are all separatecomponents interconnected though fasteners, such as screws, or othertype of connectors, including male-female tapers as illustrated in FIGS.15 and 16. The adapters 112, 112 a shown in FIGS. 3 d and 5 a include amale taper 148 which can be received in the female taper of 120 of thehead 108, 108 a, and a male taper 160 which can be received in thefemale taper 123 of the humeral stem 114.

In the embodiments illustrated in FIGS. 5 b and 7, the cup 110 may bereplaced by a bearing base 170, which is also an adapter, and a bearing172 that can be fitted to the base 170. The bearing base 170 has a maletaper 174 configured to be received in the female taper 123 of thehumeral stem 114. Examples of bearings 172 with symmetric ornon-symmetric and eccentric bearing surfaces 176 are shown in FIGS. 11a-11 c. In the embodiment of FIG. 7, the bearing base 170, includes afemale taper 178 adapted to receive the male taper 140 of the head 108b.

In the embodiment of FIG. 12, the cup 110 may be replaced by a bearing180 that is fitted in a bearing base 182 with mating male taper 184 andfemale taper 186, or with a bearing 180 that includes only a liner 188.The bearing base 182 may include a modular or integral glenoid stem 190.

Referring to FIGS. 1 and 2, for example, the implant assembly 100 may beused as follows. The humeral stem 114 is inserted in the resectedhumerus 102. The adapter 112 is attached to the head 108 by insertingthe male taper 130 into the female taper 120. For traditional shoulderarthroplasty, the cup 110 is attached to the glenoid 104, and theadapter 112 is attached to the proximal end 115 of the humeral stem 114,such that the convex surface 116 of head 108 articulates with theconcave surface 124 of the cup 110. For reverse shoulder arthroplasty,the cup 110 is attached to the proximal end 115 of the stem humeral 114and the adapter 112 is attached to the resected glenoid 104 such thatthe convex surface 116 of head 108 articulates with the concave surface124 of the cup 110. Although the same adapter 112 can be used for boththe traditional and the reverse shoulder arthroplasty procedures,glenoid-specific adapters 112 may be chosen, either as integralcomponents or built from modular parts that include male tapers 130,trays 128 and glenoid stems 134.

It will be appreciated that the individual components of the implantassembly 100 may be made using a variety of materials, including metaland plastic. The head and the stem may be made of metallic material,such as a cobalt chrome alloy, for example. Porous coating may beprovided for the proximal end of the stem. The cup may be made ofpolyethylene or metal or a combination thereof, such as polyethylenebearing or lining and metal base. The adapter can be typically made ofmetal.

Other exemplary embodiments are illustrated in FIGS. 5 a, 5 b, 6 a, 6 b,7, and 12-14. In FIG. 5 a, the male taper 140 of the head 108 b can alsobe inserted directly into the female taper 123 of the humeral stem 123.Alternatively, an adapter 112 b having a male taper 162 and a femaletaper 164 may be provided. The adapter 112 b may be also used in theembodiments shown in FIGS. 5 b, 6 a, and 6 b.

In the embodiments of FIGS. 13 and 14, the male taper 148 of the adapter112 a can be received in the female taper 120 of the head 108 for thetraditional shoulder arthroplasty shown in FIG. 13, and in the femaletaper 144 of the bearing 192 for the reverse arthroplasty shown in FIG.14. Similarly, the male taper 130 of the glenoid adapter 112 may bereceived in the female taper 120 of the head 108 for the reverseshoulder arthroplasty, and in the female taper 144 of the bearing 192for the traditional shoulder arthroplasty.

While the invention has been described in the specification andillustrated in the drawings with reference to a preferred embodiment, itwill be understood by those skilled in the art that various changes maybe made and equivalents may be substituted for elements thereof withoutdeparting from the scope of the invention as defined in the claims. Inaddition, many modifications may be made to adapt a particular situationor material to the teachings of the invention without departing from theessential scope thereof. Therefore, it is intended that the inventionnot be limited to the particular embodiments illustrated by the drawingsand described in the specification as the best modes presentlycontemplated for carrying out this invention, but that the inventionwill include any embodiments falling within the foregoing descriptionand the appended claims.

1. A method for selectively performing reverse and traditionalarthroplasty for a shoulder joint that includes a humerus and a glenoid,the method comprising: providing a head, a cup and a humeral stem;providing a humeral adapter for attaching the head to the humeral stemin traditional arthroplasty; providing a glenoid adapter for attachingthe head to the glenoid in reverse arthroplasty; selecting one of thehumeral and glenoid adapters; and performing the correspondingarthroplasty utilizing the head, the cup, the humeral stem and theselected adapter.
 2. The method of claim 1, wherein the humeral andglenoid adapters are the same adapter.
 3. The method of claim 2, whereinthe adapter includes a first male taper selectively attachable to one ofthe humeral stem and a glenoid stem.
 4. The method of claim 3, whereinthe adapter includes a second male taper configured to be received in afemale taper of the head.
 5. The method of claim 1, wherein performingthe corresponding arthroplasty includes: attaching the glenoid adapterto the glenoid; attaching the glenoid adapter to the head; attaching thecup to the humeral stem; and articulating the head with the cup.
 6. Themethod of claim 1, wherein performing the corresponding arthroplastyincludes: attaching the humeral adapter to the humeral stem; attachingthe humeral adapter to the head; attaching the cup to the glenoid; andarticulating the head with the cup.
 7. The method of claim 6, whereinattaching the glenoid adapter to the glenoid includes attaching aglenoid stem to the adapter and implanting the glenoid stem to theglenoid.